Art of stencil manufacture



Patented July 22, 19 30 NITED STATES PATENT 0mm ALEX BBo'oKING DAVIS, or CINCINNATI, OHIO, .assIe orv TO A. 18, max COMPANY, or

- cHIcAe LLINoIs, A coRroaA'rIoN or ILLINOIS ART OF STENCI Ho Drawing.

This invention relates to the art of stencil manufacture, and more particularly relates to stencil'sheets for stencil duplicating machines and to a process of making the same.

5 The principal object of this invention is to provide va stencil sheet which is inexpensive to manufacture, durable, of good quality, capable of being cut by' typewriter and stylus, and whereby excellent results may be obtained. Another object of my invention is to provide a process for manufacturing such stencil sheets with uniform high quality, quickly and inexpensively.

Other objects of my invention will be in N part obvious and in part pointed out here-.

inafter.

Many forms of type and stylus impressi ble stencils have been made and a description of them appears in the literature bearing, on

the prior art, and of these, a considerable number have been made from cellulose and its compounds. Of the particular group of cellulose compounds which are desirable for the manufacture of stencils, the cellulose ethers are applicable, and of the ether group,

' I have found that the benzyl ethers are apparently the least expensive, probably most easily prepared, and the quality of stencil sheets obtained therefrom is such as to make wthis compound highly desirable for the purpose and'a valuable addition to the art.

The structure of cellulose is such that it possesses a number of free hydroxyl groups in the molecule, and several of these are points of attack. The replacement of one or more hydroxyl hydrogen atoms by the benzyl radical C I-LC H will yield a series of benzyl.

ethers of cellulose, any one of which in our experience, by the use of proper solvents and modifiers, will give satisfactory sheets when their solutions are deposited upon a porous base sheet by means of a volatile solvent. The resulting-stencil sheets are readily type and stylus impressible and yield large numbers of copies when used with the usual types of duplicating machines. Of the several isomeric benzyl ethers which may be prepared, we prefer to use one which may be made approximately as follows:

59 500 grams of refined cellulose is digested L mn uraorunn Application filed August 5, 1926. seriarNo. 127,487.

for two days at room temperature with a solution 1,000 grams of sodium hydroxide in 3,000 cc. water. 3,000 grams of benzyl chlo-' ride is now added and the mixture heated to 100 degrees C. for seven hours, either by direct fire or upon a boiling water bath to which salt hasbeen added to raise the boiling point. The excess of benzyl chloride is now distilled. 'olfwith steam, and the resulting pulpy, fibrous mass washed-with Water, then with alcohol and finally with ether to dehydrate it and is then dried. This material is now again treated with caustic soda in the same proportion and for the same time, and this treatment is followed with a second treatment with benzyl chloride in the same proportion, and after removal of the excess of benzyl chloride by steam, is'washed and dehydrated in the same manner as previously described. The ultimate dried product shows a yield of approximately 700 grams, most of which is readily soluble in ethyl acetate, and this ethyl acetate solution can' now be directly com pounded with other modifying agents toproduce masses from which stencils can be made by drawing over or floating upon the surface thereof porous base sheets such as Japanese yoshino paper, and a satisfactory stencil results immediately the volatile solvents have evaporated. Y

[In detail, the stencil mass may be compounded as follows:

The ethyl acetate solution of the cellulose benzyl ether made as above described is ad;

.justed to aconcentration of 5%. Into 200 grams of this solution, 40 grams of castor oil, 40 grams of'benzoyl butyl tartrate and. .15 grams of halogenated hydrocarbon, such ,as tetra or hexa chlor naphthalene, are added. The castor oil and benzoyl butyl tartrate readily mix with the solution, and the halogenated. hydrocarbon, usually solid, quickly dissolves in the mass, or a solution is brought about by warming, if necessary. Pigments or soluble dyestuffs may now be added to lend any desired color to the mass in order to phtain a colored stencil sheet and afford v1s'1 bility to that the sheet. 7

The mass is now poured into su1table trays ype or stylus impressions upon I or pans and there are floated or drawn over the surface porous basesheets such as J apanese yoshino paper, and the excess removed f are found to be highly satisfactory for use on duplicating machines and are either type or stylus impressible. They possess good tensllc strength and wearing qualities, are not subject to deterioration from the action of molds or bacteria and possess the advantage of being only slightly inflammable in comparison with sheets of the same character made from nitrocellulose.

I do not restrict myself 'for the purpose of this invention to the particular isomeric benzyl ether resulting from the process given above, since cellulose benzylated to a lesser or greater extent will yield satisfactory stencil sheets. Moreover, other aralkyl ethers of cellulose which are suitable for present purposes may be formed by the process described erein or by other known methods from compounds, such as parachlor benzyl chloride, which contain substituted benzyl radicles, as well as from compounds, such as phenyl ethyl alcohol, which contain benzyl radicles having additional carbon atoms in their side chains. The expression a benzyl ether of cellulose is, therefore, intended to cover broadly all such .compounds. Nor is the invention to be otherwise limited save byth scope of the appended claims.

What I claim is 2-- 1. A type impressible stencil sheet coating including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethyl ethers of cellulose.

2. A type impressible stencil sheet coating includinga benzyl ether of cellulose.

3. A type impressible stencil sheet coating including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethyl ethers of cellulose and a modifying agent.

"4. A type impressible stencil sheet coating including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethyl ethers of cellulose, a modifying agent and a lubricant.

5. A type impressible stencil sheet coating including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethy-l ethers of cellulose, a modifying agent, a'lubricant and coloring matter. I

6. A type impressible stencil sheet coating including a benzyl ether of cellulose and'a modifying agent.

7. A type impressible stencil sheet coating including a benzyl ether of cellulose, a modifying agent and a lubricant.

9. The process ofmanufacturing a type and stylusimpressible stencil sheet by depositing upon a. porous base sheet by means of a volatile solvent a homogeneous film including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethyl ethers of cellulose.

10. The process of manufacturing a type and stylus impressiblestencil sheet by depositing upon a porous base sheet by means of a volatile solvent a homogeneous film including in its composition a benzyl ether of cellulose.

11. The process of manufacturing a type and stylus impressible stencil sheet by depositing upon a porous base sheet by means of a volatile solvent a homogeneous film including in its composition a material selected from the' benzyl, phenyl ethyl ethers o fying-agent.

12. The process of'manufacturing a type and stylus impressible stencil sheet by depositing upon a porous base sheet by means of a volatile solvent a homogeneous film including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethyl ethers of cellulose, a modifying agent and a lubricant.

13. The roeess of manufacturing a type and stylus impressible stencil sheet by depositing upon a porous base sheet by'means of a volatile solvent a homogeneous film including in its composition a material selected from the benzyl, parachlor-benzyl and phenyl ethyl'ethers of cellulose, a modifying agent, a lubricant and coloring matter.

14. The process of manufacturing atype and stylus impressible stencil sheet by depositing upon a porous base sheet by means of a volatile solvent a homogeneous film includinug in its composition a benzyl ether of cell ose and a modifying-agent.

15. The

cellulose and a modiprocess of manufacturing a type and-stylus impressible stencil sheet by depositing upon a porous base sheet by means of a volatile solvent a homogeneous film including in its composition a benzyl ether of cellulose, a modifying agent and a lubricant.

16. The process of manufacturing a type and stylus impressible stencil sheet by depositing upon a porous base sheet by means of a volatile solvent a homogeneous film including in its composition a benzyl ether of cellulose, a modifying agent, a lubricant and coloring matter.

This specification signed this 26th day of July, 1926. ALEX BROOKING DAVIS.

8. A type impressible stencil sheet coating including a benzyl ether of cellulose, a modi- 'fying agent, a In ricant andcoloring matter.

fparachlor-benzyl and 

